mirror of https://github.com/CGAL/cgal
85 lines
2.6 KiB
TeX
85 lines
2.6 KiB
TeX
\begin{ccRefClass} {Residue}
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\label{Residue}
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\def\ccTagOperatorLayout{\ccTrue}
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\ccDefinition
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The class \ccRefName\ represents a finite field $\Z{/p\Z}$,
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for some prime number $p$. \\
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The prime number $p$ is stored in a static member variable.
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The class provides static member functions to change this value.
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{\bf Note that changing the prime invalidates already existing objects
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of this type.}
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However, already existing objects do not lose their value with respect to the
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old prime and can be reused after restoring the old prime.
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Since the type is based on double
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arithmetic the prime is restricted to values less than $2^{26}$.
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The initial value of $p$ is 67111067.
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In case the flag \ccc{CGAL_HAS_THREADS}
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is undefined the prime is just stored in a static member
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of the class, that is, \ccRefName\ is not thread-safe in this case.
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In case \ccc{CGAL_HAS_THREADS}
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the implementation of the class is thread safe using
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\ccc{boost::thread_specific_ptr}. However, this may cause some performance
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penalty. Hence, it may be advisable to configure \ccc{CGAL} with
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\ccc{CGAL_HAS_NO_THREADS}.
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\ccInclude{CGAL/Residue.h}
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\ccIsModel
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\ccc{Field}\\
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\ccCreation
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\ccCreationVariable{x}
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\ccConstructor{Residue();}
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{introduces a variable \ccVar, which is initialized with zero;}
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\ccGlue
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\ccConstructor{Residue(const Residue& m);}
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{copy constructor;}
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\ccGlue
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\ccConstructor{Residue(int i);}
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{introduces a variable \ccVar, which is initialized with $i \% p$;}
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\ccGlue
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\ccConstructor{Residue(long i);}
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{introduces a variable \ccVar, which is initialized with $i \% p$;}
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\ccOperations
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\ccMethod{static int set_current_prime(int p);}{
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Static member function;\\
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sets current prime to the given value and returns the old prime. }
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\ccGlue
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\ccMethod{static int get_current_prime();}{
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Static member function;\\
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returns the value of the current prime.
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}
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\ccGlue
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\ccMethod{int get_value() const;}{
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Returns the value of \ccVar.
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}
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\ccFunction{Residue operator+(Residue a);}{}\ccGlue
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\ccFunction{Residue operator-(Residue a);}{}\ccGlue
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\ccFunction{Residue operator+(Residue a,Residue b);}{}\ccGlue
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\ccFunction{Residue operator-(Residue a,Residue b);}{}\ccGlue
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\ccFunction{Residue operator*(Residue a,Residue b);}{}\ccGlue
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\ccFunction{Residue operator/(Residue a,Residue b);}{}\ccGlue
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\ccMethod{Residue & operator+=(Residue a);}{}\ccGlue
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\ccMethod{Residue & operator-=(Residue a);}{}\ccGlue
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\ccMethod{Residue & operator*=(Residue a);}{}\ccGlue
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\ccMethod{Residue & operator/=(Residue a);}{}\ccGlue
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\ccFunction{Residue operator==(Residue a,Residue b);}{}\ccGlue
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\ccFunction{Residue operator!=(Residue a,Residue b);}{}\ccGlue
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\end{ccRefClass}
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